data definition within plpgsql

Hi,

I tried this code (to be inserted within a larger psql script)

do $_$
declare
next int;
begin
select max(id) + 1 into next from items;
execute 'create temp sequence tmp_ids start $1' using next;
end
$_$ language plpgsql;

but that reports a syntax error near $1.
What is the proper way of doing that?

Best regards
Wolfgang Hamann